Development, Optimization, and Preclinical Testing of an Impedimetric Aptamer-Based Platinum Wire Biosensing Platform for Cardiac Biomarkers

Abstract

Cardiovascular diseases (CVDs) are the leading national cause of death, impacting nearly 92.1 million Americans and accounting for 801,000 deaths annually. Unfortunately, CVDs are clinically silent until serious complications arise, thus allowing CVDs to go undetected or even be misdiagnosed at earlier stages. In addition, while biomarker testing and other cardiovascular tests can lead to earlier diagnoses, these tests are usually not ordered unless the probability of the patient having a CVD is high due to the expenses, effort, and time required. Therefore, a rapid point-of-care device would be highly useful for screening CVD conditions. This research effort was designed to fabricate a biosensing platform using aptamers and electrochemical impedance spectroscopy to rapidly detect two of the most prominent CVDs, myocardial infarction (MI) and congestive heart failure (CHF). To detect these two diseases, we screened for corresponding biomarkers Troponin T (TnT) and Brain Natriuretic Peptide (BNP). The first aim focused on fabricating platinum electrode disks using vertically aligned platinum wires cast in epoxy, and optimization of electrode diameter and surface polish. The second aim assessed optimal incubation times, concentrations, and functionalization layer combinations required for sensitive biosensing of biomarkers. The results demonstrated the feasibility of the platform, importance of surface parameters, and significance of each functionalization layer in constructing the biosensor. The third aim focused on testing fully optimized biosensor platforms against rat whole blood samples to assess the impact of (and correct for) factors in whole blood on the biosensor. The corrected biosensor model was tested against clinically derived human serum samples to determine whether the corrected model could accurately detect BNP concentrations. The results demonstrated preliminary efficacy of fabricated biosensor platforms in both serum and whole blood. However, further investigation is required to affirm model accuracy and to miniaturize the platform into a point-of-care device in the future